This invention relates to a decorative member having a decorative face on the surface of its base and a transparent layer covering the decorative face with a lens effect and more particularly to a technique for use in preparing personal outfittings such as buttons, cuffs, pendents; utility articles such as nail clippers and key holders; and outer automobile decorative parts such as side molding and ornaments.
Of decorative members of the sort described above, those for use in automobiles must meet the most severe quality requirements in view of actual environmental conditions. Taking side molding as an example, Japanese Patent Application (OPI) No. 221741/83 discloses those shown in FIGS. 1 through 3.
FIG. 1 is a perspective view showing the basic construction of a conventional decorative member, which is prepared by forming a channel 2 on the surface of an extrusion-molded base 1 in a continuous length, arranging a solid decorative face 4 on the surface of a floor 3 through the channel 2 in one body or separately and further forming a transparent layer 5 with a lens effect in such a manner as to cover the decorative face 4, an adhesive layer 6 and separate paper 7 being provided on the underside of the base 1 for sticking the above combination to the body of an automobile.
FIG. 2 is a sectional view showing the basic construction of another conventional decorative member. Unlike the one shown above, this decorative member has not a base 1 but a transparent layer 5 on the surface of a foil member 8, an adhesive layer 6 and a separate paper 7 on the underside of the adhesive layer 6.
FIG. 3 is a sectional view showing the basic construction of still another conventional decorative member, which is formed of an extrusion-molded base 1, a transparent layer 5 provided on the surface of a foil member 8 shown in FIG. 2. The decorative member is equipped with an adhesive layer 6 stuck onto the underside of the base 1.
The transparent layer 5 in the case of each above-described decorative member is formed through the method disclosed by Japanese Pat. No. 37492/77 or one similar thereto, the method comprising blending unhardened resin (e.g., unsaturated polyester) with a hardening agent in a given percentage, pouring the mixture onto the decorative face 4 of the base 1 to form the unhardened resin into a transparent layer with the flow properties and surface tension, and hardening the product by heating it.
FIG. 4 shows a concrete example of the above decorative member applied as vehicular side molding. In constrast to the basic construction of FIG. 1, the base 1 has no channel 2 but a flat decorative face 4 and the transparent layer 5 is so formed as to cover the decorative face 4. The adhesive layer 6 as well as the separate paper 7 (not shown) is also stuck to the underside of the base 1 as in the case of FIG. 1.
In the decorative member shown in FIG. 4, the lens effect of the transparent layer 5 is not satisfactorily utilized since the decorative face 4 is flat and its decorative expression tends to be monotonous. It is therefore called for to provide the decorative face 4 with solid decoration by making the decorative face 4 rugged, as shown in FIG. 5.
During the process of making the decorative face 4 rugged, when the transparent layer 5 is poured onto the decorative face 4, air is dragged in the corners (edges) of the rugged portions on the surface of the decorative face 4 and apt to be left in the edges of the rugged portions, thus forming tiny air bubbles a resulting from the air thus left unremoved until the decorative member is completely hardened. Moreover, such air bubbles a tend to produce craters or so-called sink marks, waves on the surface of the transparent layer 5 because of the difference in liner material expansion and changes in its volume as the temperature of the bubbles a changes.
FIG. 6 shows another concrete example of the decorative member in the form of a partial sectional view parallel to the longitudinal direction thereof. In contrast to what is shown in FIG. 1, the base 1 has not the channel 2 and the decorative face 4 is bent at an obtuse angle in the portion close to its end, whereas two faces 9, 10 constituting the decorative face 4 intersect in that portion. The adhesive layer 6 and the separate paper 7 of FIG. 1 are omitted in FIG. 6. If the faces 9, 10 constituting the decorative face 4 of the decorative member are not linear, excessive resin will flow into the portion of the face 10 under the influence of gravity when unhardened resin is poured onto the surface and consequently the transparent layer 5 uniform in thickness as shown in FIG. 6 is unobtainable. Conventionally, a decorative member having a flat decorative face 4 is formed first as shown in FIG. 7 and a portion close to the end thereof is bent to obtain what has the faces 9, 10 shown in FIG. 6.
The decorative member of FIG. 6 thus obtained has roundness in its bent portion 11 where the faces 9, 10 of the decorative face 4 intersect. The roundness is unavoidably produced because of the following reasons: the base 1 has a certain thickness; the tensile stress produced in the longitudinal direction of the bent portion results in a slim thickness d in the direction of thickness; and so forth. As a result, it has been impossible to obtain a decorative member with such a decorative effect as is capable of providing a sharply bent portion 11.